Algunas recomendaciones:
- S. Keshav, "An Engineering Approach to Computer Networking. ATM Networks, the Internet and the Telephone Network", Ed. Addison-Wesley. Capitulo 8
- John C.Bellamy, "Digital Telephony", 3ed edition, Ed. John Wiley & Sons. Capitulos 1 y 5
- W. Stalling, "Data and Computer Communications", 8th edition, Ed. Prentice Hall. Capitulo 10
